How does the word ladder game work?
You get a start word and an end word, both four letters long. Type a word that differs from the last one by exactly one letter, in the same position, and it becomes the next rung. Keep going until you reach the end word. Every step must be a real word; the game checks each one as you add it.
A game is 3 ladders: an easier one, a middle one and a harder one, each needing between 3 and 6 steps at the fewest. Undo takes back a step; Show me gives up on a ladder and shows one of the shortest ways through.
How is your Word Ladder result calculated?
Your result is the total steps you used on the ladders you solved, compared with the fewest steps possible for those ladders. Matching the fewest is Perfect; a few extra steps still rates Excellent or Good. A ladder you asked to be shown doesn't count towards either total, and the result says how many you solved.
| Rating (steps for three ladders) | Fewest 12 | Fewest 13 | Fewest 14 | Fewest 15 |
|---|---|---|---|---|
| Perfect | 12 | 13 | 14 | 15 |
| Excellent | 13 | 14 | 15–16 | 16–17 |
| Good | 14–16 | 15–17 | 17–18 | 18–20 |
| Fair | 17–21 | 18–23 | 19–25 | 21–27 |
| Keep trying | 22+ | 24+ | 26+ | 28+ |
The fewest steps for each ladder come from a breadth-first search over the whole word list, and the site's tests repeat that search for every ladder.
Which words count?
Any four-letter word in the ENABLE word list, a public-domain list made for word games: 3,903 words of four letters. It includes plurals, past tenses and some rarer words, but no proper names or abbreviations. Each ladder was chosen so that a shortest way through exists using common words, and that is the one Show me reveals.
Some words are dead ends: 65 four-letter words in the list have no neighbour one letter away at all. Others are crossroads; CARE has 33.
How do you solve a word ladder?
Count the letters that differ first: each step changes one, so a ladder can never be shorter than that number. COLD and WARM differ in all four letters, and the fewest is 4: COLD, CORD, WORD, WARD, WARM. When a letter can't change directly, you need a detour through a letter you change twice.
- Change consonants first. In this word list a consonant can be swapped for 3.4 other letters on average, a vowel for only 1.4, so a vowel you need to change is the harder step to fit in.
- Head for busy words. A four-letter word has 10.8 neighbours on average, but words ending in -ARE have 24.6 and -INE 23.7: good places to turn.
- Try working backwards. Change the end word towards the start, then join the two halves.
Who invented the word ladder?
Lewis Carroll, who said he invented it on Christmas Day 1877. He called it “Word-links” in his diary in March 1878, and published it as “Doublets” in the magazine Vanity Fair from the 29 March 1879 issue, with a book following later that year. His own example turns HEAD into TAIL in five steps: HEAD, heal, teal, tell, tall, TAIL. The puzzle has also been called word golf and laddergrams.
For more word puzzles, try the Cryptogram or the Word Scramble.